Aircraft: A320
Phase of flight: Parked
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy

While taxing out for departure; a maintenance issue caused us to return to the gate. Contract Maintenance was called and the problem was cleared. During our second attempt to taxi out we experienced the same maintenance issue and returned to the gate. This time; Contract Maintenance deferred the problem and we proceeded to taxi out for departure a third time. During our third attempt to takeoff we received an additional failure during initial power application; and the Captain promptly rejected the aircraft well below 20 knots and we taxied to the gate without issue. During these three maintenance occurrences an approximate elapsed time of 3 hours and 45 minutes had elapsed. While Contract Maintenance proceeded to address the brake system failure; the Captain and Gate Agent deplaned the passengers. After the aircraft was fixed and ready for departure for the fourth attempt; I reviewed my elapsed flight duty period and availability period. Since being on standby reserve; my accumulated duty time was approximately 13 hours and 45 minutes. I determined with the help of my Captain that the required flight time to return would have caused me to have an accumulated time of approximately 16 hours and 45 minutes. More than likely this time would have increased due to re-boarding and an air start. I promptly contacted Crew Scheduling to discuss this issue and was immediately confronted with a defensive attitude and an unwillingness to discuss what could potentially be a violation of CFR 117.21. I was placed on hold for a short time and when the Scheduler returned he stated that the three of them working that night were in agreement that I could complete 18 hours of total duty. 16 hours 2 of which could be from an extension period. I asked the Scheduler how he knew this and he was unable to give me a valid reference. I tried explaining to him the information detailed in the company guide but he quickly explained that it was wrong. I asked to speak to a Supervisor and was transferred; and this individual told me to call back in a few minutes and proceeded to hang up. I called the assistant Chief Pilot and discussed the issue with him; stating I would violate CFR 117.21 if I flew the flight after having been delayed all afternoon. He discussed the issue of fatigue after having a potential duty day of 17 hours upon arrival. He informed me he wanted to research the maximum duty times and the possibility of extension and would call me back shortly. After speaking to him I called scheduling to see if they had time to research my specific situation. Scheduling informed me that I was legal to fly and could be extended into an 18 hour duty day. I tried to reason with him and read to him the guide to flight duty periods published by the company; but he proceeded to hang up on me a second time. I quickly called the Chief Pilot back and he informed me that he had discussed my issue with another individual and they concluded that I was no longer legal to accept the flight and would land beyond my duty period maximum limits (16 hours). He stated he would call scheduling and explain this to them; and within five minutes of ending that call my Captain received word from the Gate Agent that Dispatch had cancelled the flight due to maintenance. Keep in mind that all maintenance had been completed and the maintenance issue was cleared. The real reason for the cancellation should have been due to my maximum duty day; but that was never stated as the reason for cancellation. I'm filing this ASAP report due to the blatant disregard for adherence to the newly implemented Part 117 flight duty time regulations. The crew schedulers had an inadequate understanding of these rules and were unwilling to take the time to discuss them with me at the time they mattered most. My concern is the company; specifically the crew schedulers; have no regard for my responsibility under CFR Part 117. I am also concerned they lack the proper training associated with CFR Part 121.135(b) (26). Maintenance issues and delays caused this First Officer to exceed the duty and availability limitations imposed by elements of FAR 117 that were contested by Crew Scheduling and the Chief Pilot's office.